Windows, doors, skylights and structural components made from materials such as aluminum, alloys thereof, steel and plastics are known. For example, window and door assemblies may be made from aluminum alloy extrusions. Windows manufactured with an aluminum frame with thermal break components are also known. For example, manufacturers use pour-and-debridge and crimped polyamide strips to make aluminum windows with thermal breaks. The pour-and-debridge type window uses liquid polyurethane poured in the pocket of an aluminum extrusion having a pair of tubular shapes (Exterior and Interior). The urethane is poured onto an aluminum bridge that connects the tubular shapes. After the polyurethane solidifies (cures to a solid state), the aluminum backing of the pocket (the bridge that constitutes a thermal bridge) is cut away, leaving only the hardened urethane as the connection between the now separated portions of the aluminum extrusion. Upon installation of the resultant structure, e.g., in a window opening in the wall of a building, a first part of the extrusion (on one side of the thermal break) is positioned facing the outside environment and the second part of the aluminum extrusion (on the other side of the thermal break) is positioned facing the inside environment of the building. The pour-and-debridge process involves four different operations: polyurethane mixing, lancing the aluminum extrusion, abrasion conditioning of the aluminum extrusion and cutting the backing of the thermal break. This approach also provides limited thermal break depth, which limits the thermal performance of the structure in that the deeper the thermal break, the better the thermal performance of the frame. In addition, the color of the frame is limited in that the structure typically displays a single color, i.e., the color of the entire extrusion that is subsequently debridged. This implies that the Exterior and Interior are the same color.
The crimped polyamide method uses one or more extruded polyamide (or other polymer) strips that are crimped in position between the interior and exterior extrusions of a structure, e.g., a window frame. In this case, the manufacturing process requires three different operations: knurling the aluminum extrusions, inserting the polyamide strip between the extrusions and crimping the aluminum extrusions. The shear strength of the resultant crimped structure is limited, as is the thermal performance. In addition, the polyamide strips typically used are expensive, as are the dies that are used to extrude them.
Windows that use pour-and-debridge thermal breaks may have a general U factor of about 0.5 Btu/h-ft2-F and windows that use crimped polyamide may have a general U factor of about 0.3 Btu/h-ft2-F. This corresponds to about an R3 thermal resistance. Both of these technologies require a significant number of manufacturing steps and expensive manufacturing equipment. Alternative methods, apparatus and manufactures for modifying energy transfer through windows, doors and other structures remains desirable.